Steel alloy



Patented Nov. 15, 1927.

UNITED STA Tas PATENT OFFICE.

ADOLF FRY, OF ESSEN, GERMANY, ASSIGNOR TO FRIEDQKRUPP AKTIENGESELLSCHAFT,

' 6 OF ESSEN-ON-THE-RUHR, GERMANY.

STEEL ALLOY.

No Drawing. Application filed September 3, 1925, Serial No. 54,363, and in' Germany May 14, 1925.

The invention relates to steel alloys adapted to be used in manufacturing articles which are hardened in-their marginal layers by nitrogenization, as for example by the 'process' described in my Patent No. 1,487,554 and'has for its object to produce steel alloys of a-nature such as to cause the articles made of them to acquire in their marginal layers an extraordinarily high hardness "by said nitrogenization, and to be distinguished by particularly good properties of strength as to their core-zone (1n particular tenacity and insensibility to tempering brittleness).

'Thisobject is attained, according to the present invention, by the fact that the steel alloys contain 0,5 to.2% of aluminium and,

either separately or in any desired combina:

tion, 0,5 to 4% of silicon, manganese, nickel, chromium, molybdenum, tungsten, vanadium, titanium or zirconium and up to 0,6% of carbon. I

Steel alloys have already been proposed for the manufacture ofarticles which are hardened. in their marginallayers by nitrogenization at a. tem erature of less than 580 C., said steel a1 oys containing, either separately-or in any desired combination, aluminium, chromium, manganese or silicon. This proposal, however, does not yet realize the above-mentioned problem viz, to produce such articles which are to present, at the same time, a particularly increased hardness of their marginal layers and extraordinarily good properties of strength of their corezone (in particular tenacity and insensibility to tempering brittleness).

The hardness of the .marginal' zone and the said properties of strength will increase up to extraordinarily advantageous values if.

the articles are made of steel alloys containing 0,5 to 2% of aluminium and 0,5 'to 3% pf chromium.

Claims:

1. An article having nitrogen in its marginal layers and cons1sting of a steel alloy containing 0.5 to 2% of aluminium, up to 0.6% of carbon, 0.5 to 4% of an element having the properties of chromium.

2. An article having nitrogen in its marginal layers and consisting of a steel alloy containing 0.5 to 2%- of aluminium, up to 0.6% of carbon, 0.5 to 4% of a combination of elements having the properties of chromium.-.

3. An article having nitrogen in its marginal layers and conslsting of a steel alloy containing 0.5 to 2% of aluminium, up to 6% of carbon, 0.5 to 4% chromiuni..

4; An article hardened in its marginal layer by nitrogenization consisting of an alloy containing 0.5 to 2% of aluminium, up

to 0.6% "of carbon, 0.5 to 4% of an element i having the properties of chromium, and the principal portion of the remainder iron.

- 5. An article hardened in its marginal layer .by nitrogenization consisting of an alloy containing 0.5 to 2% of aluminium, up to 0.6% of carbon, 0.5 t o 4% of a combination of elements having the properties of chromium, and the remainder iron.

6. An article hardened in its marginal layer by nitrogenization consisting'of an alloy containing 0.5 to 2% of aluminium, up to 0.6% of carbon, 0.5 to 4% of chromium, and the principal portion of the, remainder 1ron. Y

The foregoing specification signed Tat- ?o2logne, Germany, this 13th day of August,

principal portion of the ADOLF Far.- 

